Thursday, 29 March 2007

More about Saturn: The hexagon.

The Cassiny Mission has captured a geometric feature encircling the north pole of Saturn. Unfortunatelly for SciFi fans, it is not a geometric monolith. Is is an hexagonal pattern, created by the confluence in high latitudes of atmosphere winds. The hexagon is similar to Earth's polar vortex, which has winds blowing in a circular pattern around the polar region. On Saturn, the vortex has a hexagonal rather than circular shape. The hexagon is nearly 25,000 kilometers (15,000 miles) across. Nearly four Earths could fit inside it.

The new images taken in thermal-infrared light show the hexagon extends much deeper down into the atmosphere than previously expected, some 100 kilometers (60 miles) below the cloud tops. A system of clouds lies within the hexagon. The clouds appear to be whipping around the hexagon like cars on a racetrack. The hexagon appears to have remained fixed with Saturn's rotation rate and axis since first glimpsed by Voyager 26 years ago. The actual rotation rate of Saturn is still uncertain.

Based on the new images and more information on the depth of the feature, scientists think it is not linked to Saturn's radio emissions or to auroral activity, as once contemplated, even though Saturn's northern aurora lies nearly overhead.

A full history coverage and complementary and high resolution images can be found in the Cassini webpage. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.